# Advanced Usage

In addition the `search`, an alternative approach to querying data is with the underlying `_search` function. Instead of using input parameters defined in the client, direct API query parameters are used. Documentation on which of these are available for each endpoint can be found [here](https://api.materialsproject.org/docs) or [here](https://api.materialsproject.org/redoc). While this information is provided, **most people can and should stick to using the standard `search` function.**

The code below is an example illustrating the difference in querying for data from the summary endpoint with volume criteria using `search` and `_search`:

```python
from mp_api.client import MPRester

with MPRester("your_api_key_here") as mpr:
    # -- Using 'search'
    docs = mpr.materials.summary.search(volume=(3,10))
    
    # -- Using '_search'
    docs = mpr.materials.summary._search(volume_min=3, volume_max=10)
```


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.materialsproject.org/downloading-data/using-the-api/advanced-usage.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.